Backup command in Powershell

I am using force command because I want to overwrite the existing site collection that I created now.

Backup-SpSite -Identity http://ibggn5456-2:7777/ -Path "D:\SiteBackupData\11052015.bak" - Force

Restore-SpSite -Identity http://ibggn5456-2:7777/ -Path "D:\SiteBackupData\11052015.back" - Force


Export-SPWeb –Identity http://ibggn5456-2:2222/ -Path "D:\SiteBackupData\PU.cmp" -Itemurl "/Lists/PU/" -Force

Import-SPWeb –Identity http://ibggn5456-2:2222/ -Path "D:\SiteBackupData\PU.cmp" -Force -IncludeUserSecurity

A complete farm backup followed by a restore:

Backup-SPFarm –Directory "D:\SiteBackupData\" -BackupMethod Full 
Restore-SPFarm –Directory "D:\SiteBackupData\" -RestoreMethod New

Back up and restore a service application:

Backup-SPFarm –Directory \\App01\SharePointBackups -BackupMethod Full –Item "Excel Services"
Restore-SPFarm –Directory \\App01\SharePointBackups -RestoreMethod New –Item "Excel Services"

Back up and restore farm configuration information only:

Backup-SPConfigurationDatabase –Directory \\App01\SharePointBackups
Restore-SPFarm –Directory \\App01\SharePointBackups –RestoreMethod Overwrite –ConfigurationOnly

Back up and restore your SharePoint content databases: 

Backup-SPFarm –Directory \\App01\SharePointBackups -BackupMethod Full –Item ContosoPortal
Restore-SPFarm –Directory \\App01\SharePointBackups -RestoreMethod New –Item ContosoPortal

Back up and restore a site collection: 

Backup-SPSite –Identity http://App01/Sites/ContosoPortal -Path \\App01\SharePointBackups\PortalSiteCollection.bak -Force
Restore-SPSite –Identity http://App01/Sites/ContosoPortal -Path \\App01\SharePointBackups\PortalSiteCollection.bak –Force

Export and import a subsite, list, or library:

Export-SPWeb –Identity http://App01/Sites/ContosoPortal/ -Path \\App01\SharePointBackups\SharedDocuments.bak -Itemurl "Shared Documents" -Force
Import-SPWeb –Identity http://App01/Sites/ContosoPortal/ -Path \\App01\SharePointBackups\SharedDocuments.bak –Force -IncludeUserSecurity

http://www.c-sharpcorner.com/uploadfile/Roji.Joy/backuprestore-of-sharepoint-2010-site-collection-using-power-shell/

http://sharepointmalaya.blogspot.in/2011/01/sharepoint-powershell-backup-and.html

For stsadm command
http://sharepointmalaya.blogspot.in/2011/01/sharepoint-stsadm-backup-and-restore.html